This invention relates to a radial-mount type disk brake having its caliper fixed stably by improving the way in which the caliper is mounted.
A typical radial-mount type disk brake is shown in FIGS. 5-7. It has bolt holes 2 formed in the caliper 1 at its disk-leading (when the disk is rotating clockwise) and disk-trailing sides to extend perpendicularly to the disk axis. Mounting bolts 3 are inserted through the bolt holes 2 and threaded into a knuckle 6 to fix the caliper 1 to the knuckle 6. This mounting arrangement provides higher rigidity of the caliper than an ordinary mounting arrangement, in which the caliper 1 is tightened by bolts extending parallel to the disk axis.
Such radial-mount type disk brakes are disclosed in unexamined Japanese patent publications 63-135623, 1-210628 and 7-12149.
In the radial-mount arrangement, as shown in FIG. 6, clearances t are formed between the bolts 3 and the holes 2 to absorb any unavoidable discrepancy in the pitch P between the bolt holes 2, and the pitch P1 between the threaded holes 7 formed in the knuckle 6.
But with this arrangement, it is impossible to fix the caliper stably enough. When braking torque acts on the caliper 1, the caliper 1 tends to turn in the direction M in FIG. 5 by angular moment by a distance permitted by the clearances t as shown by chain line in FIG. 5, if the tightening force by the mounting bolts 3 are not enough. In the state shown by the chain line, the caliper mounting portion at the disk-leading side has moved toward the disk rotor 8, while the caliper mounting portion at the disk-trailing side has moved away from the disk rotor 8. Such dislocation of the caliper tends to deteriorate the braking performance, cause uneven wear of the pads 4, and increase the brake squeaks.
An object of this invention is to prevent turning of the caliper due to the clearances between the mounting bolts and the bolt holes.